We thank Perel et al for their thoughtful reading of our study on early blood transfusions in sepsis. Perel et al correctly note that our analysis was at the hospital rather than the patient level and propose 2 additional analyses: a patient-level analysis examining the association of blood transfusions on the study outcomes and a patient-level subgroup analysis that excludes patients who received transfusions after day 2 of their hospitalization. These proposals are worthwhile extensions to our work provided that appropriate variables are used for multivariable adjustment, most notably a patient’s hemoglobin concentration over time. Unfortunately, hemoglobin data were absent from our database. Hence, we performed a hospital-level analysis, which mitigates some bias inherent in patient-level analyses.

A key finding of our study that would be lost in a patient-level analysis was the considerable variation in early transfusion rates at the...

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